1. Field of the Invention
The present invention relates generally to internal combustion engines, and in particular to heating apparatus for maintaining fuel within a predetermined temperature range.
2. Description of the Prior Art
In an internal combustion engine, the function of a carburetor is to produce a combustible fuel-and-air mixture. In the carburetor, the fuel is distributed in the form of tiny droplets within a stream of air. As a result of heat absorption on the way to the cylinder, these droplets are evaporated, so that the mixture thus becomes an inflammable gas. The efficiency of the engine is directly related to the amount of energy released by combustion of a given volume of gas/air mixture within the cylinder. The primary purpose of the carburetor is to mix the gasoline uniformly with intake air in the proper proportions to produce a good aerosol mixture with the goal of obtaining complete combustion.
In the operation of conventional carburetors, liquid fuel is aspirated from a choke tube by the suction developed within a venturi region of the carburetor air passage. The aspiration of the fuel within this relatively low pressure region causes the fuel to be finely divided into tiny droplets that are carried along in a moving air mass to the cylinder. The size of each fuel droplet produced for a given pressure and air flow rate is dependent upon the viscosity of the fuel, and the viscosity of the fuel is dependent upon its temperature. It will be appreciated that at relatively low temperatures, the fuel droplets will be larger and will be less uniformly distributed throughout the moving air mixture, thereby leading to incomplete combustion. Conversely, it will also be appreciated that as the temperature of the fuel is increased, the fuel droplets constantly diminish in size until vaporized fuel is produced. Because more complete combustion and substantially more energy can be derived from a given volume of fuel aerosol mixture in which the droplets of fuel are very finely divided and uniformly dispersed, as opposed to the same volume of air mixed with superheated fuel vapor, it is desirable to maintain the temperature of the fuel below its boiling point but substantially above the fuel tank temperature.